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Old 06-28-2017, 10:26 PM   #51
Larry Lyons
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Although I have no idea just what tail wheel spring I have it looks just like the picture above. I have no pad up front and about 5/8" stack at the back. I know apples to oranges but more data anyway. By the way my spring failed right where the two upper leafs end at the tail.


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Old 06-29-2017, 05:16 PM   #52
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Alas, the pad up front was for a reason: there's a stub of tube poking out below the level of the fabric, so that the front mounting point would be resting on a thin circle of .035" steel. I think my only choice is to add another spacer at the rear mounting point, unless I can convince my A&P to very carefully grind off that stub.

I've got the tailwheel back on so the A&P can move the plane and do whatever magic he's going to do to the rudder, and I'll be consulting with him about adding another spacer at the back mounting point.


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Old 07-19-2017, 12:53 AM   #53
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My IO540 Skybolt also had a bad case of tail wheel shimmy, neighbors said the wheel would actually spin all the way around! Anyway, I had the spring re-arched and a leaf added at the local spring shop (now I have 4). And POOF... no more problem.
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Old 07-19-2017, 03:18 AM   #54
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My IO540 Skybolt also had a bad case of tail wheel shimmy, neighbors said the wheel would actually spin all the way around! Anyway, I had the spring re-arched and a leaf added at the local spring shop (now I have 4). And POOF... no more problem.
I remember Skybolt N6JJ. Built by Louie Mohr. Don Hall had it for a while. Was one of the first Skybolts with a 540. Cool airplane with history.
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Old 07-19-2017, 05:34 AM   #55
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Oh, I see I never updated with the final outcome. We added another 1/4" aluminum pad to the rear mounting point of the main spring, and the mechanic rebuilt the tailwheel itself with new parts from Alaska Bushwheels. The main spring was already in new condition as far as I could figure out.

I don't know if it was the rebuild or the extra pad that made the difference, but a couple flights have shown no tendency to shimmy so far. No passengers yet, but that will be the next test. From what I've read, the rebuild was just window dressing (it actually made the tailwheel unlock more easily, which has not been a good thing so far), the extra angle from the new pad is what made the difference.

I'm thinking about making a demonstrator device out of a cheap caster mounted to a pivoting pad, so I can change the pivot angle easily. I haven't yet figured out how I'd power it (some kind of treadmill would be ideal), but I thought it would make an interesting video to demonstrate what happens at different pivot angles.
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Old 07-19-2017, 02:42 PM   #56
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IanJ quit day dreaming and build ribs!!!
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Old 07-19-2017, 04:40 PM   #57
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I can never satisfy you people.
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Old 07-19-2017, 05:04 PM   #58
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I can never satisfy you people.
You're flying with a pretty experienced crowd...
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Old 07-19-2017, 05:39 PM   #59
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Its easy for me to to be critical, I didn't build my aircraft, I bought it.
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Old 07-19-2017, 07:11 PM   #60
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Quit building ribs and buy that Charger in Canada for 21K then rebuild it if you need to.
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Old 07-19-2017, 07:13 PM   #61
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Nowhere to put it. Nice thing about building is that I'm on the hangar wait list now, and by the time I'm done, I might actually be to the top of the list.

Edit: plus, of course, the point of this whole endeavor is that I want to build a biplane.
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Old 07-19-2017, 07:43 PM   #62
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I'm so old I don't buy treated lumber or extended warranties on anything. I buy my flying toys, not enough time left to build.
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Old 07-20-2017, 06:45 PM   #63
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My wife asked if I wanted to build for the next 13 years or fly for the next 13 years and did I think I would still be able to get a medical at that time? SOOO I bought one. :-)
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Old 07-20-2017, 07:26 PM   #64
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Quote:
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I'm thinking about making a demonstrator device out of a cheap caster mounted to a pivoting pad, so I can change the pivot angle easily. I haven't yet figured out how I'd power it (some kind of treadmill would be ideal), but I thought it would make an interesting video to demonstrate what happens at different pivot angles.
Belt sander perhaps? Not sure if that'd be wide enough, but I think it'd probably be fast enough.
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Old 07-20-2017, 11:06 PM   #65
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My wife asked if I wanted to build for the next 13 years or fly for the next 13 years and did I think I would still be able to get a medical at that time? SOOO I bought one. :-)
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Old 07-20-2017, 11:30 PM   #66
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Belt sander perhaps? Not sure if that'd be wide enough, but I think it'd probably be fast enough.
I had that thought. I'll probably give it a try, since I have one already. It'd be the easiest way.


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